This invention relates to digital wireless communication and in particular to management of routing in a wireless network communication system. More particularly this invention relates to load balancing control systems in an environment of a multiple-band, two-way packet communication network, such as one employing frequency-hopping spread spectrum communication among a plurality of nodes. In such a network each node comprises a local autonomous node controller controlling the various channels associated with it, each of which is a radio or other link operating in a specific channel or frequency band and/or packet mode. Terminal node controllers comprise nodes of intelligence which are capable of maintaining multiple concurrently operative links via multiple nodes. The links typically operate independently of one another, concerned only with avoiding incidents of interference when a common channel is used by more than one link.
To improve efficiency of communication, it is desirable to send data to a less contested resource.
This invention was developed in the context of the Metricom Ricochet packet communication network as part of the effort to expand its usefulness beyond the 900 MHz ISM band to take advantage of other bands for subscriber to node communication while at the same time taking advantage of a backbone of wireless and wired communication links. A general familiarity with the technology is helpful background for understanding the environment of this invention.
Use of load information and of other metrics is known for use in load monitoring, control and alternative packet routing. For example, a routing protocol called IGRP deals with some of the problems encountered in using load metrics in routing. For example, in “An Introduction to IGRP,” Charles L. Hedrick of Rutgers University describes the Inter-Gateway Routing Protocol and the need to take into account the level of traffic on different paths. U.S. Pat. No. 5,253,248 of Dravida et al. of AT&T Bell Labs issued Oct. 12, 1993 describes how undesired oscillations can occur with the IGRP protocol. Therein congestion is monitored locally. However, the measurement examines only local loading of information communicated to a remote node. The present invention offers a different mechanism to measure load and to enhance performance.